Organic light-emitting device and organic light-emitting display device using the same

1. An organic light-emitting device comprising:

a first electrode;

a second electrode opposite the first electrode, the second electrode being used as an exit side;

first to n-th (n being a natural number equal to or greater than 2) stacks disposed between the first electrode and the second electrode, each of the first to n-th stacks having light-emitting layers that emit light having a same color; and

(n-1) charge generation layers disposed between neighboring ones of the first to n-th stacks, each of the (n-1) charge generation layers comprising an n-type charge generation layer and a p-type charge generation layer, wherein

the second electrode abuts on the n-th stack,

the light-emitting layer of the n-th stack is a phosphorescent light-emitting layer comprising at least one phosphorescent host and a phosphorescent dopant that emits light including a first wavelength,

the light-emitting layer of at least the (n-1)-th stack is a fluorescent light-emitting layer comprising at least one fluorescent host and a fluorescent dopant that emits light including the first wavelength,

distances from an interface between the n-type charge generation layer and the p-type charge generation layer of the (n-1)-th charge generation layer to the light-emitting layers of the n-th stack and the (n-1)-th stacks adjacent thereto are the same, or a distance from the interface between the n-type charge generation layer and the p-type charge generation layer to the light-emitting layer of the n-th stack is greater than a distance from the interface between the n-type charge generation layer and the p-type charge generation layer to the light-emitting layer of the (n-1)-th stack, and

the phosphorescent dopant of the phosphorescent light-emitting layer in the n-th stack has a peak light emission at a lower wavelength than the fluorescent dopant of the fluorescent light-emitting layer in the (n-1)-th stack.

2. The organic light-emitting device according to claim 1 ,

wherein the distance from the interface between the n-type charge generation layer and the p-type charge generation layer to the light-emitting layer of the n-th stack is 2.2 or less times distance from the interface between the n-type charge generation layer and the p-type charge generation layer to the light-emitting layer of the (n-1)-th stack.

3. The organic light-emitting device according to claim 1 , wherein the phosphorescent light-emitting layer of the n-th stack is thicker than the fluorescent light-emitting layer of the at least one of the first to (n-1)-th stacks.

4. The organic light-emitting device according to claim 1 , wherein a full width at half maximum of an emission spectrum of the phosphorescent light-emitting layer comprises a full width at half maximum of an emission spectrum of the fluorescent light-emitting layer.

5. The organic light-emitting device according to claim 2 , wherein a distance between a lower surface of the phosphorescent light-emitting layer of the n-th stack and an upper surface of the fluorescent light-emitting layer of the (n-1)-th stack ranges from 800 Å to 1200 Å.

6. The organic light-emitting device according to claim 5 , wherein a distance from the interface between the n-type charge generation layer and the p-type charge generation layer to the fluorescent light-emitting layer of the (n-1)-stack is 200 Å or more.

7. An organic light-emitting display device comprising:

a substrate having regularly arranged first to third subpixels;

a thin film transistor provided at each of the first to third subpixels; and

first to third organic light-emitting devices, each of which is electrically connected to the thin film transistor at a corresponding one of the first to third subpixels, each of the first to third organic light-emitting devices comprising a first electrode, a second electrode opposite the first electrode, the second electrode being used as an exit side, first to n-th (n being a natural number equal to or greater than 2) stacks disposed between the first and second electrodes, the first to n-th stacks having light-emitting layers that emit light having a same color, and (n-1) charge generation layers disposed between neighboring ones of the first to n-th stacks, each of the (n-1) charge generation layers comprising an n-type charge generation layer and a p-type charge generation layer,

wherein the light-emitting layers in the first to n-th stacks of each of the first to third subpixels emit light having a same color, and

wherein, in at least one of the first to third subpixels,

the second electrode abuts on the n-th stack,

the light-emitting layer of the n-th stack is a phosphorescent light-emitting layer comprising at least one phosphorescent host and a phosphorescent dopant that emits light including a first wavelength,

the light-emitting layer of at least the (n-1)-th stack is a fluorescent light-emitting layer comprising at least one fluorescent host and a fluorescent dopant that emits light including the first wavelength,

distances from an interface between the n-type and p-type charge generation layers of the (n-1)-th charge generation layer to the light-emitting layers of the n-th stack and the (n-1)-th stacks adjacent thereto are the same, or a distance from the interface between the n-type charge generation layer and the p-type charge generation layer to the light-emitting layer of the n-th stack is greater than a distance from the interface between the n-type charge generation layer and the p-type charge generation layer to the light-emitting layer of the (n-1)-th stack, and

the phosphorescent dopant of the phosphorescent light-emitting layer in the n-th stack has a peak light emission at a lower wavelength than the fluorescent dopant of the fluorescent light-emitting layer in the (n-1)-th stack.

8. The organic light-emitting display device according to claim 7 , wherein

the first to third subpixels each have light-emitting layers that emit light having different colors for corresponding ones of the first to n-th stacks, and

the first to n-th light-emitting layers of the first to third subpixels may have different thicknesses.

9. The organic light-emitting display device according to claim 8 , wherein the first to n-th stacks have a common layer that is commonly provided for the first to third subpixels, excluding the light-emitting layers.

10. The organic light-emitting display device according to claim 9 , wherein the charge generation layers are commonly provided for the first to third subpixels without disconnection.

11. The organic light-emitting display device according to claim 7 , wherein the phosphorescent light-emitting layer of the n-th stack is thicker than the fluorescent light-emitting layer of the (n-1)-th stack.

12. The organic light-emitting display device according to claim 7 , wherein a full width at half maximum of an emission spectrum of the phosphorescent light-emitting layer of the n-th stack comprises a full width at half maximum of an emission spectrum of the fluorescent light-emitting layer of the (n-1)-th stack.

13. An organic light-emitting display device comprising:

a substrate;

a first electrode of a first subpixel and a first electrode of a second subpixel on the substrate;

a first light-emitting layer on the first electrode of the first subpixel, wherein the first light-emitting layer is a fluorescent light-emitting layer including a first fluorescent dopant and is configured to emit light of a first color;

a second light-emitting layer on the first electrode of the second subpixel disposed adjacent to the first light-emitting layer, wherein the second light-emitting layer is a fluorescent light-emitting layer including a second fluorescent dopant and is configured to emit light of a second color;

a charge generation layer on the first light-emitting layer and the second light-emitting layer, comprising an n-type charge generation layer and a p-type charge generation layer;

a third light-emitting layer on the charge generation layer overlapping the first light-emitting layer, wherein the third light-emitting layer is a phosphorescent light-emitting layer including a first phosphorescent dopant and is configured to emit light of the first color;

a fourth light-emitting layer on the charge generation layer disposed adjacent to the third light-emitting layer and overlapping the second light-emitting layer, wherein the fourth light-emitting layer is a phosphorescent light-emitting layer including a second phosphorescent dopant and is configured to emit light of the second color; and

a second electrode on the third light-emitting layer and the fourth light-emitting layer,

wherein a first distance from an interface between the n-type charge generation layer and the p-type charge generation layer to the third light-emitting layer is equal to or greater than a second distance from the interface between the n-type charge generation layer and the p-type charge generation layer to the first light-emitting layer, and

the first phosphorescent dopant of the third light-emitting layer has a peak light emission at a lower wavelength than the first fluorescent dopant of the first light-emitting layer.

14. The organic light-emitting display device of claim 13 , further comprising:

a hole injection layer on the first electrode of the first subpixel and the first electrode of the second subpixel;

a hole transport layer on the hole injection layer, and overlapping the first electrode of the first subpixel and the first electrode of the second subpixel;

an electron transport layer on the first light-emitting layer and the second light-emitting layer; and

an electron injection layer on the electron transport layer and overlapping the third light-emitting layer and the fourth light-emitting layer.

15. The organic light-emitting display device of claim 13 , wherein the first light-emitting layer has a different thickness than the second light-emitting layer, and the third light-emitting layer has a different thickness than the fourth light-emitting layer.

16. The organic light-emitting display device of claim 13 , wherein:

a third distance from the interface to the second light-emitting layer is less than or equal to a fourth distance from the interface to the fourth light-emitting layer.

17. The organic light-emitting display device of claim 13 , wherein the third light-emitting layer is thicker than the first light-emitting layer, and the fourth light-emitting layer is thicker than the second light-emitting layer.

18. The organic light-emitting device according to claim 1 ,

wherein n is a natural number equal to or greater than three, and

each light-emitting layer of the other stacks excluding the (n-1)-th and n-th stacks is a phosphorescent light-emitting layer comprising at least one phosphorescent host and a phosphorescent dopant.

19. The organic light-emitting display device of claim 13 , wherein the second phosphorescent dopant of the fourth light-emitting layer has a peak light emission at a lower wavelength than the second fluorescent dopant of the second light-emitting layer.